Cartridge-fired apparatus for driving fasteners and the like

ABSTRACT

Cartridge fired fastener driver comprises a piston-ram positioned to be driven forward by explosion of the cartridge. This piston has a narrowed section encircled by a stationary ring smaller in diameter than either end of the piston-ram so that the stroke of the piston is limited to the length of its narrowed section minus the thickness of the ring.

Unlted States Patent 11 1 1111 3,871,565 Termet Mar. 18, 1975 1 CARTRIDGE-FIRED APPARATUS FOR 3,531,037 9/1910 Schneider .1 227/10 DRIVING FASTENERS AND THE LIKE 3.556 379 1/1971 Bayer 227/10 0 3,566,978 3/1971 Udert 227/10 [76] Inven r: Plerr T rmel, l Imp e ll f, 3,632,032 1/1972 Termet 227/10 Lyon 3, France [22] Filed: Feb. 22, 1973 Primary Examiner-Granville Y. Custer, Jr. [2|] APPL No: 334,943 Attorney, Agent, or Firm-Brisebois & Kruger [30] Foreign Application Priority Data [57] ABSTRACT 1972 France 7206100 Cartridge fired fastener driver comprises a piston-ram [52] U 5 Cl 227/10 positioned to be driven forward by explosion of the [51] 1114 cartridge This piston has a narrowed section encircled by a stationary ring smaller in diameter than either [58] Field of Search 227/10, 11, 130 end of the pistommm so that the stroke of the piston [56] References Cited is limited to the length of its narrowed section minus UNITED STATES PATENTS the thlckness of the ring.

1.5421586 6/1925 Rubin et a1. 227/130 6 Claims, 5 Drawing Figures I V H gt/(Ill: t 2 \zWI I 7 11 22 -12 /5 13 V; 5

CARTRIDGE-FIRED APPARATUS FOR DRIVING FASTENERS AND THE LIKE SUMMARY OF THE INVENTION The present invention relates to an apparatus for attaching two materials to each other by using nails or pins or for driving pins or similar elements into materials such as iron, concrete or wood.

The invention applies especially to a fastening apparatus powered by the explosion of a cartridge and of the so-called piston-ram or hammer" type, in which the gases deriving from the explosiion of the cartridge operate in a cylindrical chamber on the head of a piston provided with a rod which drives the fastener or stud into the receiving material.

The present invention makes it possible to adapt the gun to the nature of the work to be carried out merely by changing the piston-ram.

Thus owing to the invention a fastening apparatus can be quickly adapted merely by changing the pistonram, to insert pins in relatively soft materials which necessitate only a small amount of energy, such as for instance for attaching wooden bars provided with hooks which are secured to the floor all around a room, in order to hold the carpet which is fitted on the hooks.

The present invention relates, as a novel product of manufacture, to apparatus for driving pins or similar members of the type powered by the explosion of a cartridge and comprising a piston-ram, characterized in that the piston-ram comprises a central part and two end parts, said central part being of reduced section and moving in a stop forming ring, which is seated in the tip of the guide element of the apparatus, said ring having an orifice equal to or very slightly larger than the section of the central part of the piston-ram, but smaller than the section of either of the two end parts of the piston-ram, the end part of the piston-ram located on the side facing the explosion chamber of the cartridge having a shoulder abutting against said ring to prevent the piston-ram from leaving the guide element of the apparatus and the end part of the piston ram which engages the pin being pushed back before the firing towards the inside of the apparatus to come into contact with said ring.

The end part of the piston-ram which lies in the explosion chamber of the cartridge is advantageously connected to said central part of reduced section by a frusto-conical bearing shoulder which comes into contact with a concave surface of corresponding form which is provided on the stop forming ring.

In a preferred embodiment the part of the piston-ram which engages the pin is connected to the central part of reduced section by a surface, which defines a sharp or slightly rounded edge where it meets the cylindrical peripheral surface of the front part of the piston-ram, so that said edge can come into contact with and be gripped in a slightly conical internal bearing which is provided on the surface of the stop forming ring which is directed towards the mouth of the apparatus.

Consequently, as the piston-ram is pushed back towards the inside of the apparatus, both its positioning and its holding by a binding action are ensured due to the fact that said edge frictionally engages said partly conical shoulder.

The piston-ram is thus held in its firing position.

The stop ring according to the invention can be advantageously located in a movable tip capable of sliding with respect to the front end of the apparatus in order to stop the piston-ram when it strikes the ring, for instance in the case of firing on no load.

According to the invention, it is especially advantageous to make the piston-ram as a single part, and to make the stop forming ring in two or more parts which are radially fitted together and which are firmly held in a closed housing which is provided in the movable tip.

As can easily be seen, owing to the invention, the part of the piston-ram which strikes the pin at the moment at which the pin is driven in, is at the moment of firing, always located in a precisely determined position in relation to the remainder of the apparatus.

As a result, one can by changing the length of the part of the piston-ram facing the cartridge, modify at will the effective volume of the explosion chamber at the moment of the firing of the cartridge.

Thus it is possible to vary to a large extent the power of the apparatus to adapt it to the different works which are to be carried out.

For instance, one uses a piston-ram which has an extended length which gives an explosion chamber of a small volume to drive a pin into a hard material. On the contrary, one uses a piston-ram having a short length to give a large explosion chamber when one desires to drive the pin into a less resistant material.

The present invention has also for its object pins which can be used in the above described apparatus, and which are characterized in that they are each provided with two guiding and stop washers having the same diameter, said diameter being larger than that of the head.

Thus one can easily fasten these pins in position and one gets an excellent guiding and a good regularity of the penetration in the material.

All the features and characteristics of the invention wiil become evident in the course of the following description of several embodiments that are shown in the attached drawing, in which FIG. 1 is a schematic view in axial section of the head part of a fastener driving apparatus according to the invention,

FIGS. 2 and 3 show different embodiments of pistonrams used in the apparatus of FIG. 1,

FIG. 4 shows on a larger scale the part of the guide element provided with the stop forming ring, and

FIG. 5 is a view similar to FIG. I showing an embodiment of the light hammer" type.

On FIG. 1 there is shown in heavy lines the movable tip located at the head part of the apparatus and including the particular device of the invention and the piston-ram whereas the remainder of the guide for the piston rod has been shown in fine lines. The rear part of the apparatus, which comprises the breech and the firing device, has not been shown for it constitutes no part of the invention.

One can see on FIG. 1 the cartridge chamber 1 which includes the cartridge 2 and which opens into the explosion chamber 3 located at the left end of the bore 4 of the guide member 5.

The movable tip generally referred to as 6 is capable of sliding towards the right relative to the guide member 5 until the stop 9 of the tip comes into engagement with the shoulder 10 of complementary form which is fixed to the guide member.

The piston-ram comprises: a head 11, the diameter of which is equal to or very slightly smaller than the diameter of the bore 4', a central part 12 having a smaller diameter; and an end part 13 the diameter of which is very slightly smaller than the diameter of the bore 14 of the tip 6.

In the illustrated embodiment the bore 14 of the tip 6 has the same diameter as the bore 4 of the guide member, but this equality is not critical for the invention, and it could be possible to provide apparatus in which the bore 14 has a different diameter than that of the bore 4.

One can also see on FIG. I the stop forming ring 15 the orifice diameter of which is slightly larger than the diameter of the central part 12 of the piston-ram, but smaller than the diameters of the end parts 11 and 13 of the piston-ram.

On the drawing, the clearances between the guide member and the piston-ram have been exagerated in order that the operation of the apparatus according to the invention may be more clearly understood.

One can also see from FIG. 1 how the head 13 of the piston-ram engages a nail 16 provided with two guiding washers and the head of which is received in a recess provided on the frontal surface of the part I3 of the piston-ram.

A magnet device 17 ensures the location in position of the pin 16 during the preparation for firing.

Referring now to FIG. 4, one will now more precisely describe the characteristics of the stop forming ring 15.

This ring is received in a cup 18 which is screwed by threads 19 in a circular seat in the body of the tip 6.

The ring 15 is thus firmly held on the tip 6 in the space delimited between the internal part of the cup 18 and the surface 20 of the tip 6.

In order to permit mounting of the stop forming ring 15, the latter is made in two parts which are diametrically fitted together.

The cup 18 is mounted in the end part 6 by slipping the cup 18 (which does not include the stop forming ring 15) on the central part 12 of the piston-ram, by placing the two parts of the stop forming ring 15 around the central part 12 and then seating them in their housing in the cup l8, and screwing the cup into its housing in the tip 6.

As can be seen from FIG. 4 the stop forming ring comprises on the side facing the head of the piston-ram a frusto-conical surface 21, the form of which corresponds to the form of the shoulder 22 which connects the head 11 to the central part 12 of the piston-ram (FIG. 1).

As a result, in order to stop the piston-ram, the shoulder 22 of the latter comes into engagement against the frusto-conical surface 21 of the stop forming ring 15.

The stop forming ring 15 comprises also a cylindrical bore the diameter of which is equal to or very slightly larger than the diameter of the central part 12 of the piston-ram.

Finally, the stop forming ring 15 includes two frustoconical surfaces 24 and 25.

In the illustrated embodiment, only the frustoconical surface 25 is useful, whereas the surface 24 is simply used for connecting the frusto-conical surface 25 and the cylindrical bore 23.

As can clearly be seen on FIG. 4, the edge 27 which is delimited by the cylindrical part 13 of the end of the piston ram and the frusto-conical shoulder 26 which connects said part and the central part 12, comes into engagement with the frusto-conical surface 25 when the piston-ram is pushed back towards the left.

As a result the edge 27 is gripped by the slightly conical surface 25, thereby ensuring both a precise positioning of the piston-ram relative to the body of the driving apparatus and the holding of said piston-ram in said position whatever may be the slope given to the guide member.

Although this construction of the stop forming ring with the possibility of frictional gripping of the head part of the piston-ram represents a preferred embodiment of the invention, one could however arrange that the ring merely limits the displacement towards the inside of the piston-ram without gripping it, provided that the retention of the piston-ram in its proper position is ensured by other means. FIGS. 2 and 3 illustrate two other piston-rams which can be used in the above described apparatus.

The piston-ram of FIG. 2 is different from that shown in FIG. 1 in that its head 11a is of a shorter length. As a result, at the moment of firing (the end 13 being always held in the same position relative to the guide element) the chamber 3 in which the explosion takes place has a substantially greater volume which results in reducing the force with which the piston-ram is displaced towards the right to drive in the pin 16.

On the contrary, in the embodiment of FIG. 3, the head llb of the piston-ram is of a greater length in order to fill quite completely the chamber 3 which is a continuation of the cartridge chamber l.

Accordingly one obtains a greater propulsive force for the pin.

FIG. 3, also shows as an alternative embodiment how a pin 7 having a threaded head, can also be driven in, the head of the pin being engaged in a deeper orifice provided in the front end B of the piston-ram. Only the bottom of this orifice has the same diameter as that of the pin thread in order to avoid any binding of the latter.

One can see that the apparatus according to the invention which is of a particularly simple structure, makes it possible to adapt the power of the apparatus to requirements of the work to be carried out by using piston-rams of different lengths Furthermore, as illustrated in the embodiment shown in FIG. 5 it is possible to use the apparatus with a socalled light" piston-ram which comprises only a rear part II forming a piston and a rod part 12' having a reduced diameter which directly engages the pin to be driven in. In that case, at the moment of firing, the pin and the piston-ram are completely pushed back towards the left, the ring 15 is replaced by a ring 15 which can be made of a single piece and the internal diameter of which is sufficient to permit passage of the pin and the part 12' of the piston-ram, but insufficient to permit passage of the shoulder 22', thereby allowing it to function as a stop.

One obtains by using such a piston-ram of known type substantially high speeds for driving pins in.

Similarly by replacing the front part of the guide member by a guide member of the type 6' and a pistonram of the type l2 illustrated in FIG. 5 one can easily transform the apparatus according to the invention into an apparatus of a conventional so-called "light hammer" type which permits the communication to the pin of substantially high driving-in speeds for instance, of 150 to 180 meters per second.

The result is an apparatus which has the feature of being universal, merely by changing some pieces.

It is understood that the embodiments that have been described above are given purely by way of example and that they can modified as to detail without exceeding the scope of the invention.

What is claimed is:

1. Cartridge fired apparatus for driving fasteners and the like, said apparatus comprising a housing defining a cartridge chamber for receiving a cartridge, and an explosion chamber communicating with said cartridge chamber,

a piston-ram having one end part slidably mounted in said explosion chamber and a central part having a smaller section than either of its end parts,

a stop-defining ring encircling said central part at the end of said explosion chamber remote from said cartridge chamber, and fixed to a guiding tip encircling the other end part of said piston-ram on the side of said ring remote from said explosion chamber, said ring defining an orifice having a section at least equal to, but at most slightly larger than that of the central part of the piston-ram, and smaller than the section of either of said end parts,

and means retaining said housing and guiding tip in axial alignment with each other,

said one end part of said piston-ram defining a shoulder which abuts said ring after an explosion to prevent expulsion of said piston-ram through said guide member, while the other end part of said piston-ram defines a shoulder positioned to abut said ring when said apparatus is in firing position, before explosion of a cartridge.

2. Apparatus as claimed in claim 1 in which the shoulder on said one end part of said ram is frustoconical and the abutting surface of said ring is also frusto-conical.

3. Apparatus as claimed in claim 1 in which the shoulder on the other end part of said piston defines an edge with the peripheral surface of said other end part, which edge is received in and slightly gripped by the abutting surface of said ring, which is frusto-conical.

4. Apparatus as claimed in claim 1 in which said guiding tip and ring form part of a member which is movable within predetermined limits as a unit longitudinally of said piston-ram.

5. Apparatus as claimed in claim 1 in which said ring is made in two parts held together within said longitudinally movable member.

6. Cartridge fired apparatus for driving fasteners and the like, said apparatus comprising a housing defining a cartridge chamber for receiving a cartridge, and an explosion chamber communicating with said cartridge chamber,

a piston-ram having one end part slidably mounted in said explosion chamber and a central part having a smaller section than either of its end parts,

a stop-defining ring encircling said central part at the end of said explosion chamber remote from said cartridge chamber and fixed to a guiding tip encircling the other end part of said piston-ram on the side of said ring remote from said explosion chamber, said ring defining an orifice having a section at least equal to, but at most slightly larger than that of the central part of the piston-ram, and smaller than the section of either of said end parts, and

means retaining said housing and guiding tip in axial alignment with each other,

said ring being made in two parts and removably mounted in said apparatus so that piston-rams of different lengths may be readily introduced into and removed from said explosion chamber,

said one end part of said piston-ram defining a shoulder which abuts said ring after an explosion to prevent expulsion of said piston-ram through said guide member. 

1. Cartridge fired apparatus for driving fasteners and the like, said apparatus comprising a housing defining a cartridge chamber for receiving a cartridge, and an explosion chamber communicating with said cartridge chamber, a piston-ram having one end part slidably mounted in said explosion chamber and a central part having a smaller section than either of its end parts, a stop-defining ring encircling said central part at the end of said explosion chamber remote from said cartridge chamber, and fixed to a guiding tip encircling the other end part of said piston-ram on the side of said ring remote from said explosion chamber, said ring defining an orifice having a section at least equal to, but at most slightly larger than that of the central part of the piston-ram, and smaller than the section of either of said end parts, and means retaining said housing and guiding tip in axial alignment with each other, said one end part of said piston-ram defining a shoulder which abuts said ring after an explosion to prevent expulsion of said piston-ram through said guide member, while the other end part of said piston-ram defines a shoulder positioned to abut said ring when said apparatus is in firing position, before explosion of a cartridge.
 2. Apparatus as claimed in claim 1 in which the shoulder on said one end part of said ram is frusto-conical and the abutting surface of said ring is also frustO-conical.
 3. Apparatus as claimed in claim 1 in which the shoulder on the other end part of said piston defines an edge with the peripheral surface of said other end part, which edge is received in and slightly gripped by the abutting surface of said ring, which is frusto-conical.
 4. Apparatus as claimed in claim 1 in which said guiding tip and ring form part of a member which is movable within predetermined limits as a unit longitudinally of said piston-ram.
 5. Apparatus as claimed in claim 1 in which said ring is made in two parts held together within said longitudinally movable member.
 6. Cartridge fired apparatus for driving fasteners and the like, said apparatus comprising a housing defining a cartridge chamber for receiving a cartridge, and an explosion chamber communicating with said cartridge chamber, a piston-ram having one end part slidably mounted in said explosion chamber and a central part having a smaller section than either of its end parts, a stop-defining ring encircling said central part at the end of said explosion chamber remote from said cartridge chamber and fixed to a guiding tip encircling the other end part of said piston-ram on the side of said ring remote from said explosion chamber, said ring defining an orifice having a section at least equal to, but at most slightly larger than that of the central part of the piston-ram, and smaller than the section of either of said end parts, and means retaining said housing and guiding tip in axial alignment with each other, said ring being made in two parts and removably mounted in said apparatus so that piston-rams of different lengths may be readily introduced into and removed from said explosion chamber, said one end part of said piston-ram defining a shoulder which abuts said ring after an explosion to prevent expulsion of said piston-ram through said guide member. 